There has been employed a Cu wiring process using copper (Cu) as a wiring material of semiconductor devices. As an example of the Cu wiring process, a diffusion prevention film (barrier metal) is formed on a surface of wiring grooves formed in an insulating film by physical vapor deposition (PVD) such as sputtering. On a surface of barrier metal, a Cu film (Cu seed layer) is grown by sputtering or the like and a Cu film is further accumulated on this Cu film by electroplating or the like. Thereafter, the Cu film is abraded by chemical mechanical polishing (CMP) or the like until a surface of the insulating film is exposed to form a Cu wiring layer.
However, With recent requirements for densification of semiconductor integrated circuits, and miniaturization of the pitch and achievement of a high aspect ratio of wiring grooves and vias, it has become difficult for PVD that has generally been used in a conventional Cu wiring process to form a satisfactory film on the side wall of wiring groove and the depth part of the via. Therefore, a study has been made of an improvement in coatability of a Cu film by employing chemical vapor deposition (CVD) and atomic layer deposition (ALD) or the like in place of PVD.
For example, JP 2012-212899 A discloses that a barrier metal film is formed on a substrate by a sputtering method and a Cu film is formed on this barrier metal film by a CVD method. Thereafter, an annealing treatment is performed at 100 to 400° C. so as to improve adhesion between the barrier metal film and the Cu film, and also a Cu film is formed to form a Cu wiring.
There has been known, as a raw material used in a CVD process of formation of a Cu film, for example, β-ketonate-based organometallic complexes such as Cu(hfac)(tmvs) and Cu(hfac)2. For example, JP 2000-219968 A discloses an example of a raw material for Cu-CVD process using Cu(hfac)(tmvs) suited for formation of a Cu film having good film quality.